Análise genética de espécies arbóreas de um remanescente da Mata Atlântica "Parque Estadual Mata dos Godoy" em Londrina-PR, por marcadores moleculares de AFLP e Microssatélites

AUTOR(ES)
DATA DE PUBLICAÇÃO

2009

RESUMO

The intense fragmentation process of the tropical forests is one of the most important issues of the XXI century, being directly responsible for environmental degradation, climate changes and the loss of biodiversity. Such process is the focus of many studies that intend, primarily, to identify the effect of devastation in the gene pool of species that occupy degraded areas. The Tibagi River basin, situated in the east-center portion of the Paraná State with an approximate area of 24.711 Km2, comprising around 13% of the area of the State. Extending through different climate zones, the vegetation of the Tibagi River basin is highly heterogeneous. However, due to the colonization process that occurred in the last 50 years, the flora of the region has being highly impacted and the native forest cover corresponds, nowadays, to only 3.8% of it´s original area. Within these fragments many populations of tree species are more or less isolated. Molecular markers techniques have being widely used in studies of anthropogenic impacted areas. The aim of present study was to investigate two tree species (Campomanesia xanthocarpa e Luehea divaricata), that occur in the Tibagi River basin, using AFLP and microsatellite markers. Two natural populations of Campomanesia xanthocarpa originated from the north and south portions of the Parque Estadual Mata dos Godoy, Lower Tibagi region, were studied using AFLP markers. Six selective primer combinations were amplified generating 181 markers, of wich, 92.27% and 92.82% were polymorphic for the south and north populations, respectively. Values of gene diversity (HS) for the populations from south and north portions of the fragments yielded similar results (0.3292 and 0.3221, respectively). The FST for both populations was 0.1801, with a genetic distance of 0.1006 between populations. The principal coordinate analysis PCoA showed the formation of two distinct groups, with some individuals from the south population clustering with the individuals from the north population. Bayesian analysis for the number of cluster K, demonstrated that in 61.8%, individuals were signed to the populations from which they were sampled. The levels of genetic conservation are considered satisfactory and represent valuable information on the natural populations of C. xanthocarpa studied. For studies of the species Luehea divaricata, we isolated, through the development of a microsatellite enriched library, ten SSR loci. The amplification of these loci generated, in 42 individuals, a total of 45 alleles, with an average of 4,5 alleles per locus. The average polymorphic information content (PIC) was 0,546 and the values of observed (HO) and expected heterozigosity (HE) varied from 0 to 0.929 and 0.194 to 0.821, respectively. Four loci exhibited linkage disequilibrium (p ≤ 0.01). Primers were tested for cross-species amplification within nine species of the Malvaceae family. These preliminary results demonstrate the usefulness of these microsatellites in accessing the genetic structure of Luehea divaricata and related genera.

ASSUNTO(S)

genética florestal genética de populações degradação ambiental forest genetics populations genetics

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